Weather seal for cylinder lock mechanism



Feb. 25; 1964 E. N. JACOB! 3,122,013

WEATHER SEAL FOR CYLINDER LOCK MECHANISM Filed May 25, 1961 3 Sheets-Sheet l dward N Jacob: 32

Feb. 25, 1964 E. N. JACOB] 3,122,013

WEATHER SEAL FOR CYLINDER LOCK MECHANISM F iled May 25, 1961 3 Sheets-Sheet 2 Feb. 25, 1964 E. N. JACOB] 3,122,013

WEATHER SEAL FOR CYLINDER LOCK MECHANISM Filed May 25, 1961 5 Sheets-Sheet 3 3&056

JMJM MJ .Edwa r .NIJaaabz United States Patent 3,122,013 WEATHER SEAL FOR CYLINDER LOCK MECHANISM Edward N. Jacobi, Milwaukee, Wis., assignor to Briggs &

Stratton Corporation, Milwaukee, Wis., a corporation of Delaware Filed May 25,1961, Ser. No. 112,616 9 Claims. (Cl. 7tl455) This invention relates to lock mechanisms of the type generally used on doors and deck covers of automotive vehicles, and refers more particularly to a weather seal for a cylinder lock of that type, by which dust and moisture are prevented from entering the lock mechanism to thus assure its operativeness under all weather conditions.

A common type of lock which is now in widespread use for exterior automotive installations, such as doors and rear deck lids, comprises a lock body having a bore therein which opens to its front end, a lock cylinder rotatable in the bore and having a forwardly opening key receiving slot accessible from the front of the lock body, and an annular bezel secured to the front portion of the body and which holds the cylinder assembled in the body. The opening in the bezel is large enough to receive a proper key which is insertable through the bezel and into the key slot in the cylinder for effecting rotation of the cylinder between locked and unlocked positions.

To prevent dust and moisture from entering the key receiving slot in the cylinder and damaging the lock mechanism or interfering with its operation, such a lock is usually provided with a weather seal that comprises, in many cases, a disc like cap behind the bezel which is biased forwardly into sealing engagement with the inner marginal edge portion of the bezel by means of small compression springs reacting between the cap and the cylinder. The cap has a key aperture therein which registers with the key receiving slot in the cylinder and which is normally closed by a movable shutter.

A weather seal of this type which is now in common use is disclosed in the patent to E. N. Jacobi, No. 2,690,071. In that mechanism the shutter by which the key aperture in the cap is normally closed is mounted for swinging motion. 'In its closed position, toward which it is biased, it fiatwise overlies the rear face of the cap, across the key aperture therein. When a key is projected through the key aperture, its front end engages the shutter to swing the same to an open position in which the shutter projects rearwardly from the cap and clears the key aperture to allow the key to be inserted into the key receiving slot in the cylinder.

The mounting for the shutter in this mechanism comprised a hinge pin that had its end portions bent rearwardly and staked into closely fitting grooves in the front end portion of the cylinder. Surrounding the medial portion of the hinge pin were the convolutions of a coiled torsion spring with radially extending arms that reacted against the cylinder while urging the shutter toward its closed posiiton and biasing it forwardly toward firm flatwise sealing engagement with the rear face of the cap.

Although it was satisfactory enough to enjoy widespread use, the weather seal mechanism just described had a serious disadvantage from the manufacturing standpoint in that its parts could not be handled as a subassembly. The hinge pin and the torsion spring surrounding the same could be staked into the front of the cylinder, but the shutter, which had hook-like projections that engaged around the hinge pin to serve as hinges, was readily separable from the hinge pin and cylinder 3,122,013 Patented Feb. 25, 1964 until the bezel was secured over the front of the lock body to hold it in place.

While failures of this weather seal mechanism were by no means common, they did occur from time to time, and they arose from the fact that there could be slight variations from lock to lock in the axial spacing between the rear face of the bezel and the hinge pin upon which the shutter was pivoted. Such variations grew out of an accumulation of tolerances in the length of the lock body relative to that of the cylinder, the clinching of the bezel onto the front of the lock body, and the securement of the hinge pin to the cylinder. It could thus happen that the distance between the hinge pin and the rear face of the bezel would be so large, in certain cases, that the arms of the torsion spring engaged the shutter and the cap at a substantial forwardly inclined angle. Under those circumstances, when the shutter was swung rearwardly by a key inserted into the key aperture in the cap, it produced a force component lengthwise of the spring arm which was carried into the coils of the spring and which could be severe enough to distort and damage the spring coils. Since the shutter spring was very small and was tensioned nearly to its elastic limit, this distortion of the coils weakened the spring so that it failed to maintain the shutter engaged against the rear face of the cap with sufficient sealing force to exclude moisture from the lock mechanism. Even if the spring escaped damage, the forward inclination of the spring arms made it difficult to swing the shutter rearwardly, so that the shutter tended to have an undesirable sticky and unyielding action against a key being inserted into the key aperture.

By contrast with this prior weather seal mechanism, it is a general object of this invention to provide a weather seal having a swingable shutter, but wherein the Weather seal mechanism constitutes a complete subassembly that can be handled independently of the lock body, lock cylinder and bezel, and which subassembly comprises a disc like cap that is adapted to be engaged against the rear face of the bezel, a shutter adapted to normally close the key aperture in the cap, means hingedly mounting the shutter on the cap for swinging motion toward and from a normal closed position of the shutter, and biasing means for holding the shutter in its closed position.

It is also an object of this invention to provide a Weather seal which can be installed on a lock of the type to which the weather seal of the aforesaid Jacobi patent is applicable, and which requires little or no modification of the body, cylinder or bezel of the lock to adapt them for the seal of this invention, so that conversion to production of locks with the present weather seal can be accomplished without incurring high costs for die changes or tooling.

Another object of this invention is to provide, in a cylinder lock mechanism of the type having an annular bezel secured to the front of a lock body in which a lock cylinder is rotatable, a weather seal which comprises a disc like cap that overlies the rear face of the bezel to close the opening therein, a shutter which is hingedly mounted for swinging motion to and from a closed position flatwise overlying the rear face of the cap to normally close a key aperture therein, a hinge pin upon which the srutter is mounted for such swinging motion, and a coiled torsion spring surrounding the hinge pin by which the shutter is biased to its closed position, wherein the hinge pin is connected to the cap to thus insure that the shutter will have good flatwise sealing engagement with the cap when it is in its closed position, and to further insure that the torsion spring will have its arms fiatwise engaged against the rear faces of the shutter and cap, rather than projecting toward them at oblique angles.

From the foregoing it will be apparent that it is another object of this invention to provide in a lock mechanism of the character described a weather seal comprising a disc like cap that is at all times engaged under forward bias with a bezel secured to the front of the lock body, and a shutter mounted for swinging motion toward and from a closed position flatwise overlying the rear surface of the cap and closing a key receiving aperture therein, wherein both the shutter and a spring by which the shutter is biased toward its closed position are carried by the cap itself, to thus insure that the spring will always engage the shutter in such a manner as to bias it firmly to its closed position and yet afford a smooth easy opening action of the shutter when it is engaged by a front end of a key projected through the key aperture in the cap.

Thus the broad general object of this invention may be stated as residing in the provision of a weather seal for a cylinder lock mechanism of the character described, capable of being manufactured at lower cost than heretofore conventional weather seals by reason of the fact that its main components can be preassembled with one another and handled as a subassembly, and which furthermore, affords assurance of more satisfactory operation, a longer useful life and a better seal against the entry of dirt and moisture into the lock mechanism on which it is installed.

Another specific objective of the invention, realized in one form thereof, resides in the provision of a weather seal of the character described wherein a torsion spring by which the shutter is biased toward flatwise engagement with the cap, overlying the rear surface thereof, also serves to bias the cap forwardly into sealing engagement with a bezel on the front of the lock body and to urge the cylinder rearwardly in the lock body and confine it against rattling.

With the above and other objects in view which will appear as the description proceeds, this invention resides in the novel construction, combination and arrangement of parts substantially as hereinafter described and more particularly defined by the appended claims, it being understood that such changes in the precise embodiments of the hereindisclosed invention may be made as come within the scope of the claims.

The accompanying drawings illustrate two complete examples of physical embodiments of the invention constructed according to the best modes so far devised for the practical application of the principles thereof, and in which:

FIGURE 1 is a front elevational view of a cylinder lock embodying the weather seal of this invention with a portion of the bezel at the front of the lock body shown broken away;

FIGURE 2 is another view of the cylinder lock shown in FIGURE 1, in which portions are shown in side elevation and portions are shown in longitudinal section taken on the plane of the line 22 in FIGURE 1;

FIGURE 3 is a view similar to FIGURE 2 but with the portion thereof shown in section taken on the plane of the line 3--3 in FIGURE 2;

FIGURE 4 is a perspective view of a portion of a cylinder lock mechanism and the components of the weather seal of this invention shown in disassembled relation thereto; and

FIGURE 5 is a fragmentary view similar to FIGURE 2, but on an enlarged scale and showing a modified embodiment of the invention.

Referring now more particularly to the accompanying drawings, the numeral 5 designates the body of a cylinder lock mechanism such as is commonly used for the doors and deck covers of automobiles. The body is provided with a bore 6 which opens to the front thereof and in which a lock cylinder 7 is rotatably received. The bore 6 preferably opens to the front to the body through a countcrbore 8, and the front end of the lock cylinder is enlarged to substantially fit the counterbore.

A proper key, a portion of which is indicated at 9, is insertable into a forwardly opening key slot 10 in the lock cylinder for operation of a tumbler mechanism (not shown) in the cylinder and for rotation of the cylinder relative to the lock body. In the present case the key slot 10 opens to a well 11 at the front of the cylinder, the mouth of which is defined by a circumferential rim 12 that extends nearly entirely around the cylinder, and in which a valve like sealing member 13 is received. The sealing member 13 is in the form of a disc or cap of circular outline, as best seen in FIGURE 4, and preferably, though not necessarily, is formed of a relatively stiff piece of stainless sheet steel of spherical configuration, with the convex side thereof facing forwardly and projecting slightly beyond the rim 12. The diameter of the cap is approximately equal to the inside diameter of the circumferential rim 12, so that the latter holds the cap coaxial with the lock cylinder and against lateral shifting relative thereto.

The cap or sealing member 13 is retained in place on the front of the lock cylinder by an annular bezel 14 that encircles the front of the locx body and is fixed thereto in any suitable manner, such as by having its outer peripheral edge portion 15 clinched or rolled around an enlarged head portion 16 on the front of the lock body. It will be seen that the bezel, in addition to serving as a trim for the front of the lock, holds the cylinder against forward displacement out of the lock body.

The coaxial aperture 17 in the bezel is of smaller diameter than the cap 13 so that the marginal edge portions of the bezel which define its aperture extend radially inwardly beyond the periphery of the cap and overlie the front side thereof to hold the cap in the circumferential rim 12 on the front of the lock cylinder. The bezel 14 is preferably formed of stainless sheet steel of somewhat thinner stock than that of the cap 13, so that the marginal portions of the bezel which define its aperture 17 have a degree of resiliency and are capable of slight deflection in a direction axially of the lock cylinder.

The cap is biased forwardly into sealing engagement with the bezel by means of compression springs 18, described hereinafter. However, the key receiving slot 10 in the cylinder is accessible to a key inserted through the opening 17 in the bezel by reason of the provision of a key aperture 19 in the cap which is at all times in register with the key receiving slot in the cylinder and which is normally closed by a shutter 20.

According to this invention the cap 13 is connected to the lock cylinder in a manner which constrains the cap to rotate with the cylinder but does not interfere with limited tilting as well as substantially fiatwise back and forth motion of the cap axially of the cylinder. For this purpose rearwardly projecting substantially diametrically opposite lugs 29 and 29 on the periphery of the cap are received in substantially closely fitting notches or cutouts 22 in the rim portion 12 on the cylinder. The lugs 29 and 29, which also perform other functions described hereinafter, hold the cap with its key opening in perfect register with the key slot It) in the cylinder.

The forward biasing force exerted by the coiled compression springs 18 is received by substantially diametrically opposite radially outwardly projecting cars 21 on the cap, which are circumferentially spaced from the lugs 29 and 29'. The springs 18, which react against the front of the cylinder, are steadied and held with their axes parallel to the axis of the cylinder by having their rear portions received in small forwardly opening wells 23 in the front of the cylinder. It will be seen that the springs 18 urge the cap 13 forwardly into self-centering engagement with the bezel and thus assure firm contact between the convex or spherical front face of the cap and the ad jacent inner marginal edge portion of the bezel 14, around the entire circumference of the aperture 17 in the bezel.

Preferably the cap 13 is also provided with a small rearwardly projecting gutter or lip 24 which is located at its bottom when the cylinder is in its locked position of rotation, and which comprises the locating lug 29. Any moisture that might enter the front of the lock body is directed by this gutter to a drain hole in the front of the lock body, at the bottom thereof, to prevent it from seeping back along the bore in the body and thus entering the cylinder.

It is a feature of the weather seal of this invention that the shutter 20 by which the key aperture 19 in the cap is normally closed, a hinge pin 26 upon which the shutter is swingably mounted, and a torsion spring 27 by which the shutter is biased to a closed position, are all carried by the cap itself, and comprise with it a subassembly 28 (see FIGURE 4) that can be preassembled apart from the lock mechanism and that can be handled and transported without danger of its parts becoming disassembled. To this end the locating lugs 29 and 29 are apertured, as at 30, to receive the end portions of the straight hinge pin 26, and it will be noted that the lugs are so arranged on the cap that the hinge pin is disposed entirely to one side of the key aperture 19 in the cap and in a plane normal to the axis of the cap. Since the key aperture is substantially rectangular, to closely fit the key 9, the hinge pin preferably extends parallel to one of its longer sides.

The shutter 20 is substantially rectangular and 1s so formed that its front face has the same spherical curvature as the back face of the cap, in order to establish the most effective weather proof seal for the key opening 19. From one of the longer side edges of the shutter project a pair of integral hooks 31 that are adapted to loosely engage around the hinge pin 26 to mount the shutter for swinging back and forth motion between its closed position and an open position in which the shutter projects rearwardly from the cap, into the front end portion of the cylinder. When the shutter is thus mounted, the hooks 31 are disposed closely adjacent to the lugs 29 and 2 and axlally inwardly of them, so that the lugs and hooks cooperate in preventing displacement of the shutter axially along the hinge pin. The coiled torsion spring 27, which has its convolutions surrounding the hinge pin, is in turn held against axial displacement by the hooks 31, since the axial length of the spring is substantially equal to the distance between the hooks.

Attention is directed to the fact that the hooks 31 fit quite loosely on the hinge pin. This not only makes for ease of assembly but insures that the shutter will be free to move bodily forwardly, under the biasing force of the spring 27, into good flatwise sealing engagement with the ihe end portions of the torsion spring 27 are straight and project radially to provide a pair of arms 32 which flatwise overlie and react against the rear face of the cap. The medial portion of the spring 27 is bent to a substantially U-shape and likewise projects radially from its convolutions to provide an arm 33 that flatwise overlies and reacts against the rear face of the shutter. In biasing the shutter toward its closed position and into flatwise engagement with the rear face of the cap, the arms 32 and 33 of the torsion spring impose a rearward reaction upon its convolutions whereby the coils of the spring are maintained firmly engaged with the hinge pin 26 and thus frictionally prevent axial displacement of the hinge pin out of the lugs 29 and 29', even though the hinge pin is perfectly straight along its entire length and has a diameter substantially smaller than that of the openings in the lugs 29 and 29' in which the end portions of the hinge pin are received.

When the cap is assembled to the front of the lock, the hinge pin is received in rather closely fitting forwardly opening groove 35 in the front of the lock cylinder and is thus positively confined against axial displacement. Similarly the arms 32 which project radially from the ends of the torsion spring 27 are received in forwardly opening recesses 36 in the front of the cylinder providing opposite fore-and-aft extending surfaces 37 against 6 which the arms 32 are engageable and by which the spring is thus held against axial displacement.

Because the spacing between the hinge pin and the rear face of the cap is accurately established by the lugs 29 and 29 and the apertures 30 in said lugs, that spacing can easily be kept within very close limits in the manufacture of the weather seals of this invention, and consequently the biasing force which the torsion spring exerts against the shutter can likewise be held within accurately maintainable limits. For the same reason, assurance is had that the spring arms 32 and 33 will engage the cap and shutter flatwise, rather than projecting toward them at oblique angles, thus assuring that the shutter will have a smooth action when swung rearwardly by a key projected through the key aperture 19, and that the spring will have a long useful life.

It will be apparent that the hinge pin 26, torsion spring 27 and shutter 20 can be preassembled onto the cap 13 to form a unitary subassembly which can be handled and transported without special care or precautions to prevent disassembly. t will also be apparent that once this subassembly is made up, assembly of the entire weather seal is very simple, and consists merely of inserting the compression springs 18 into the wells 23 in the front of the cylinder, setting the subassembly 28 in place within the rim 12 on the cylinder (being sure the locating lugs 29 and 29' are received in the recesses 22), placing the bezel 14 on the front of the lock body, and clinching or rolling the rim of the bezel around the head 16 on the body.

In the modified embodiment of the invention illustrated in FIGURE 5, the shutter biasing spring 27 is relied upon to bias the cap 13 forwardly into engagement with the bezel 14, thus eliminating the need for separating cap biasing springs corresponding to the springs 18 in the previously described embodiment of the invention. In this case the apertures 30' in the lugs 129 and 129' on the cap 13' extend rearwardly a substantial distance, while the forwardly opening grooves 35' in the cylinder, in which the outer end portions of the hinge pin 26 are received, are substantially shallow, so that the hinge pin engages the bottoms of the grooves 35' and is held thereby in forwardly spaced relation to the rear edges of the apertures 39'.

The coiled shutter biasing spring 27 in the FIGURE 5 version of the invention is identical with that previously described, and its radial arms 32 and 33 respectively apply forward biasing force to the cap 13' and to the shutter 2th. The rearward reaction to the biasing force of spring arms 32 and 33 is transmitted to the hinge pin 26 by the convolutions of the spring 27, and the hinge pin, in turn, transmits such rearward reaction force to the cylinder, through its engagement with the bottoms of the grooves 35'. In other words, the engagement of the hinge pin with the cylinder causes the spring 27 to urge the shutter and cap forwardly toward the bezel and the cylinder rearwardly into the lock body, holding opposing circumferential abutments 41 and 42 on the cylinder and lock body, respectively, firmly but freely rotatably engaged under a biasing force which prevents rattling of the cylinder in the body.

The embodiment of the invention illustrated in FIG- URE 5 requires that the shutter spring 27 be capable of exerting a substantially large biasing force, and further requires that the axial dimensions of the lock body, cylinder, bezel, and apertures 30' be accurately held during manufacture of the lock. However, the smooth shutter action afforded by the mechanism of this invention allows a substantially large amount of forward bias to be exerted upon the shutter without rendering its action objectionably stiff and in some cases the elimination of the springs 18 might warrant the additional care required to maintain the required close tolerances in the axial dimensions just mentioned.

From the foregoing description taken together with the accompanying drawings, it will be apparent that this 7 invention provides a weather seal for a cylinder lock which is inexpensive and easily assembled, and which provides good assurance against the entry of moisture and other foreign matter into the lock mechanism and has a long useful life.

What is claimed as my invention is:

1. In a lock mechanism of the type comprising a lock body having a bore opening to its front end, and a key controlled lock cylinder rotatable in the bore and having a forwardly opening well in its front end portion and a key slot which opens forwardly into said well: a disc-like cap in the well in the cylinder having a key opening which registers with the key slot in the cylinder; a pair of integral circumferentially spaced apart lugs on said cap projecting rearwardly from its peripheral edge portion, said lugs being disposed on a line which lies entirely to one side of the key opening; a pin having its opposite end portions engaged in said lugs to be supported by them; a key-hole shutter adapted to flatwise overlie the rear face of the cap, over the key opening; integral hook-like hinge means extending from an edge portion of the shutter and engaged around the pin to mount the shutter for swinging motion between a closed position flatwise overlying the rear face of the cap and an open position projecting rearwardly from the cap and disposed entirely to said one side of the key opening; a shutter spring having a medial portion engaged with said pin and having opposite radially projecting arms engaging the rear faces of the cap and of the shutter to bias the shutter toward its closed position and to urge the shutter flatwise into firm engagement with the rear face of the cap so that the shutter seals the key aperture therein; an annular bezel having its outer marginal edge portion secured to the front of the lock body, the opening in said bezel being smaller in diameter than the cap but large enough to receive a key; and other spring means reacting between the cylinder and the cap to urge the cap forwardly into sealing engagement with the bezel.

2. An article of manufacture, a weather seal for preventing entry of moisture and the like into the front of a forwardly opening key slot in a lock cylinder which is rotatable in a bore in a lock body, said weather seal comprising: a disc-like cap having a key aperture therein which is adapted to register with the key slot in a lock cylinder, and having integral circumferentially spaced apart lugs projecting from its peripheral edge portion in one direction parallel to its axis; a hinge pin having its end portions received in said lugs on the cap to be supported thereby in a plane substantially normal to the axis of the cap and spaced in said one direction from the adjacent cap surface; a shutter having integral projection means engaged around said pin by which the shutter is connected to the cap for swinging motion relative to the cap between a closed position in which the shutter flatwise overlies the cap, covering the key aperture, and an open position in which the shutter projects in said direction from the cap; and a shutter spring having radially oppositely projecting arms respectively engaging the cap and the shutter and having a medial portion engaging the pin between said lugs, the reaction of said spring against the cap and the shutter biasing the shutter to its closed position and the reaction of the spring against said pin holding the pin against axial displacement out of said lugs.

3. The weather seal of claim 2, further characterized by the fact that said projection means on the shutter comprises a pair of coaxial hooks projecting from one edge portion of the shutter and which are spaced from one another along said edge of the shutter by a distance such that they are axially inwardly adjacent to said lugs on the cap, so that said lugs cooperate with the hooks in preventing displacement of the shutter in directions lengthwise of the pin; and further characterized by the fact that said shutter spring comprises a coiled torsion spring, the convolutions of which surround the pin, said spring having an axial length such that its end convolutions are closely adjacent to said hooks to be held by them against displacement lengthwise of the pin, and the arms of said spring comprise radially projecting straight end portions which flatwise overlie the cap, and a substantially U-shaped radially projecting medial portion which flatwise overlies the shutter.

4. A lock of the type comprising a body with a bore opening to its front, a cylinder rotatable in the bore and having a forwardly opening key slot, an annular bezel secured to the front of the lock body and through which a key can be inserted into the key slot in the cylinder, a cap behind the bezel biased forwardly into engagement with the bezel to close the opening therein, said cap having a key aperture which registers with the key slot in the cylinder, and a shutter behind the cap normally biased to a closed position flatwise overlying the rear face of the cap, across the key aperture, but movable to a position clearing the key aperture by a key pushed through the key aperture and into the key slot, said look being characterized by: a pair of rearwardly projecting spaced apart lugs on the cap, both located on the same side of the keyhole aperture; and a hinge pin carried by said lugs and on which the shutter is hingedly carried for swinging motion toward and from its closed position 5. The lock of claim 4, further characterized by the fact that the shutter is biased to its closed position by a shutter spring having a medial portion engaging the hinge pin and reacting against the same and having radially projecting arms engaging the shutter and the cap and reacting against them.

6'. in a lock of the type comprising a body with a bore opening to its front, a cylinder in the bore in the body having a key slot opening to its front into which a key can be inserted from the front of the body for rotation of the cylinder relative to the body, and an annular bezel secured on the front of the body and through which a key is insertable into the cylinder, a weather seal for preventing entry of moisture and the like into the key slot in the cylinder, comprising: a disc-like cap confined behind the bezel to close the opening therein and having a key aperture adapted to register with the key slot in the cylinder; a pair of coiled compression springs 'eacting between the cylinder and said cap to bias the cap forwardly into snug sealing engagement with the rear face of the bezel, said springs being seated in forwardly opening wells in the front of the cylinder, near the periphery of the cylinder and substantially diametrically opposite one another; rearwardly projecting lugs on said cap, radially spaced to one side of the key aperture and spaced apart a substantial distance; a hinge pin having its end portions engaged in said lugs on the cap; a shutter having integral hook like projection means thereon engaged around the pin to mount the shutter for swinging motion toward and from a closed position in which the shutter flatwise overlies the rear face of the cap, across the key aperture; and a coiled torsion spring having its convolutions embracing the pin and having arms which react against the rear surface of the shutter and the rear face of the cap to urge the shutter toward its closed position and into snug flatwise engagement with the rear face of the .cap and thereby normally seal the key aperture in the cap.

7. In a lock mechanism of the type comprising a lock body having a bore opening to its front end, and a key controlled lock cylinder rotatable in the bore and having a forwardly opening key slot: a disc-like cap having a key opening therein; means on the lock 'body cooperating with edge portions of the cap to rotatably mount the cap in front of the cylinder, with the key opening in the cap registering with the key slot in the cylinder; a pair of integral circumferentially spaced apart lugs on said cap projecting rearwardly from its peripheral edge portion; a pin having its opposite end portions engaged in said lugs to be supported by them entirely to one side of the key opening in the cap; a key hole shutter adapted to flatwise overlie the rear face of the cap, over the key opening therein; means mounting the shutter for swinging motion about an axis substantially parallel to that of said pin between a closed position flatwise overlying the rear face of the cap and an open position projecting rearwardly from the cap and disposed entirely to said one side of the key opening; and a shutter spring having a medial portion engaged with said pin and having oppositely projecting arms engaging the rear faces of the cap and of the shutter to bias the shutter toward its closed position.

8. The lock mechanism of claim 7 wherein said means mounting the shutter for swinging motion comprises: integnal hinge means on the shutter, extending from an edge portion thereof and engaged around the pin.

9. A lock of the type comprising a body with a bore opening to its front, a cylinder rotatable in the bore and having a forwardly opening key slot, an annular bezel secured to the front of the lock body and through which a key can be inserted into the key slot in the cylinder, a cap behind the bezel biased forwardly into engagement 10 with the bezel to close the opening therein, said cap having a key aperture which registers with the key slot in the cylinder, and a shutter behind the cap normally biased to a closed position flatwise overlying the rear face of the cap, across the key aperture but movable to a position clearing the key aperture by a key pushed through the key aperture and into the key slot, said lock being characterized by: a pair of lugs on the cap, integral therewith and projecting rearwardly from circumferentially spaced portions of its periphery; a hinge pin carried by said lugs and spaced to one side of the keyhole aperture; and means on the shutter cooperating with the hinge pin to hingedly carry the shutter for swinging motion about the axis of the hinge pin toward and from its closed position.

References Cited in the file of this patent UNITED STATES PATENTS 2,665,031 Jaco bi Oct. 13, 1953 2,680,965 Jacobi June 15, 1954- 2,690,071 Jacobi Sept. 28, 1954 2,747,397 Jacobi May 29, 1956 

4. A LOCK OF THE TYPE COMPRISING A BODY WITH A BORE OPENING TO ITS FRONT, A CYLINDER ROTATABLE IN THE BORE AND HAVING A FORWARDLY OPENING KEY SLOT, AN ANNULAR BEZEL SECURED TO THE FRONT OF THE LOCK BODY AND THROUGH WHICH A KEY CAN BE INSERTED INTO THE KEY SLOT IN THE CYLINDER A CAP BEHIND THE BEZEL BIASED FORWARDLY INTO ENGAGEMENT WITH THE BEZEL TO CLOSE THE OPENING THEREIN, SAID CAP HAVING A KEY APETURE WHICH REGISTERS WITH THE KEY SLOT IN THE CYLINDER, AND A SHUTTER BEHIND THE CAP NORMALLY BIASED TO A CLOSED POSITION FLATWISE OVERLYING THE REAR FACE OF THE CAP, ACROSS THE KEY APETURE, BUT MOVABLE TO A POSITION CLEARING THE KEY APETURE BY A KEY PUSHED THROUGH THE KEY APETURE AND INTO THE KEY SLOT, SAID LOCK BEING CHARACTERIZED BY: A PAIR OF REARWARDLY PROJECTING SPACED APART LUGS ON THE CAP, BOTH LOCATED ON THE SAME SIDE OF THE KEYHOLE APERTURE; AND A HINGE PIN CARRIED BY SAID LUGS AND ON WHICH THE SHUTTER IS HINGEDLY CARRIED FOR SWINGING MOTION TOWARD AND FROM ITS CLOSED POSITION. 